Long Term Evolution (LTE) is a mobile telecommunications standard, promulgated by the European Telecommunications Standards Institute (ETSI), for wireless communication involving mobile user equipment, such as mobile devices and data terminals. LTE networks include existing Fourth Generation (4G), and 4.5 Generation (4.5G) wireless networks. The goals of LTE included increasing the capacity and speed of wireless data networks, and redesigning and simplifying the network architecture to an Internet Protocol (IP)-based system with reduced latency compared to the Third Generation (3G) network architecture.
Next Generation mobile networks have been proposed as the next evolution of mobile wireless networks, such as the existing 4G and 4.5G LTE mobile networks. Next Generation mobile networks, such as Fifth Generation New Radio (5G NR) mobile networks, are expected to operate in the higher frequency ranges, and such networks are expected to transmit and receive in the GigaHertz band with a broad bandwidth near 500-1,000 MegaHertz. The expected bandwidth of Next Generation mobile networks is intended to support download speeds of up to about 35-50 Gigabits per second. The proposed 5G mobile telecommunications standard, among other features, operates in the millimeter wave bands (e.g., 28, 38, and 60 GigaHertz (GHz)), and supports more reliable, massive machine communications (e.g., machine-to-machine (M2M), Internet of Things (IoT)). Next Generation mobile networks, such as those implementing the 5G mobile telecommunications standard, are expected to enable a higher utilization capacity than current wireless systems, permitting a greater density of wireless users, with a lower latency. Next Generation mobile networks, thus, are designed to increase data transfer rates, increase spectral efficiency, improve coverage, improve capacity, and reduce latency.
The Internet Protocol (IP) multimedia subsystem (IMS), defined by the 3rd Generation Partnership Project (3GPP), is an architectural framework for implementing IP-based telephony and multimedia services. IMS defines a set of specifications that enables the convergence of voice, video, data and mobile technology over an all IP-based network infrastructure. In particular, IMS fills the gap between the two most successful communication paradigms—cellular and Internet technology, by providing Internet services everywhere using cellular technology in a more efficient way. Session Initiation Protocol (SIP) is the main protocol for IMS. SIP is an application layer control (signaling) protocol for creating, modifying and terminating sessions (e.g., voice sessions) with one or more participants.
A Voice over Long Term Evolution (VoLTE) network is based on the IMS network and provides Internet Protocol (IP) based voice and data service via a network complying with the LTE standard. VoLTE has more voice and data capacity than other wireless networks, while using less available bandwidth due to the use of smaller packet headers.